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    <script>
        // 假设你现在要根据后端返回的数据 
        let arr = [
            {
              "id": "604e21feb205b95968e13129",
              "pid": "0",
              "name": "总裁办"
            },
            {
              "id": "604e223fb205b95968e1312b",
              "pid": "0",
              "name": "人事部",
            },
            {
              "id": "604e2251b205b95968e1312c",
              "pid": "0",
              "name": "财务部",
            },
            {
              "id": "604e2262b205b95968e1312d",
              "pid": "604e2251b205b95968e1312c",
              "name": "财务核算部"
            },
            {
              "id": "604e227db205b95968e1312e",
              "pid": "604e2251b205b95968e1312c",
              "name": "税务管理部"
            },
            {
              "id": "604e2297b205b95968e1312f",
              "pid": "604e2251b205b95968e1312c",
              "name": "薪资管理部"
            },
            {
              "id": "6051ad90e93db6522c1d00d2",
              "pid": "0",
              "name": "技术部"
            },
            {
              "id": "6051adb6e93db6522c1d00d3",
              "pid": "6051ad90e93db6522c1d00d2",
              "name": "Java研发部"
            },
            {
            "id": "6051add6e93db6522c1d00d4",
            "pid": "6051ad90e93db6522c1d00d2",
            "name": "Python研发部"
            },
            {
            "id": "6051adefe93db6522c1d00d5",
            "pid": "6051ad90e93db6522c1d00d2",
            "name": "Php研发部"
            }
        ]

        //1.准备一个新数组
        const newData = []

        //2.开始第一次遍历，筛选第一层
        for (let i = 0; i < data.length; i++) {
            if (data[i].pid ==='0') {
                data[i].children = []  

                data[i].children = []
            }
            //3，第二次遍历，判断pid等于id的项放到对应的children
        }

    </script>
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